Human Sperm Characteristics with Regard to Cobalt,Chromium, and Lead in Semen and Activity of Catalase in Seminal Plasma

Biological Trace Element Research - We analyzed cobalt (Co), chromium (Cr), and lead (Pb) concentrations in human semen and catalase CAT activity in seminal plasma and the effects of their...     

A novel method for cloning of coding sequences of highly toxic proteins

Background

During standard gene cloning, the recombinant protein appearing in bacteria as the result of expression leakage very often inhibits cell proliferation leading to blocking of the cloning procedure. Although different approaches can reduce transgene basal expression, the recombinant proteins, which even in trace amounts inhibit bacterial growth, can completely prevent the cloning process.

Selective Reconstitution of the Tonoplast H+-ATPase of the Crassulacean-Acid Metabolism Plant Kalanchoë daigremontiana

IA detergent removal technique was used to reconstitute solubilized tonoplast proteins of mesophyll cells of the CAM plant Kalanchoë daigremontiana into phosphatidylcholine liposomes. The proteoliposomes were able to hydrolyse ATP and to pump protons across the vesicle membrane. Both activities were inhibited by nitrate, an inhibitor of V-type ATPases. Freeze-fracture micrographs confirmed the incorporation of membrane proteins into liposomes. Increase of specific ATP-hydrolysis activity compared to solubilized tonoplast proteins and SDS-PAGE analysis of reconstituted proteins in comparison with the polypeptide pattern of the purified tonoplast H⁺-ATPase from the same plant source indicated a highly selective reconstitution of the tonoplast H⁺-ATPase.     

Bone marrow angiogenesis and proliferation in B-cell chronic lymphocytic leukemia

OBJECTIVE: To assess angiogenesis and the proliferative activity of bone marrow in patients with chronic lymphocytic leukemia (CLL) in relation to the bone marrow infiltration pattern. STUDY DESIGN: Bone marrow samples were obtained by trephine biopsy from 46 patients with B-cell CLL (B-CLL). Infiltration pattern was diffuse in 20 patients and nondiffuse--i.e., nodular, interstitial or mixed--in the remaining 26 patients. Ten normal bone marrow samples were used as a control group. Studies were carried out by immunohistochemical staining of paraffin-embedded bone marrow samples. Angiogenesis was assessed in the zones of highest vascular density (hot spots), visualized by the expression of endothelial antigen CD34 and expressed as a number of microvessels per high-powerfield (hpf) (final magnification, 400x). Proliferative activity was estimated by the expression of nuclear protein Ki-67, cyclin A and mean number of nucleolar organizer regions (AgNORs). RESULTS: Microvessel density was higher in B-CLL marrow than in normal marrow (30.1 and 16.44 per hpf, respectively) and was higher in the diffuse than nondiffuse pattern (33.6 and 27.5 per hpf, respectively). B-CLL bone marrow also showed higher proliferative activity, as assessed by mean number of AgNORs, than did normal marrow (1.52 and 1.25, respectively) and a higher mean percentage of cyclin A-positive cells (7.5 and 6.8, respectively). In contrast, mean Ki-67 expression was similar in B-CLL and the control group. Mean AgNORs number, Ki-67 and cyclin A-positive cell percentage were significantly higher in B-CLL marrow with a diffuse as compared to nondiffuse involvement pattern (AgNORs, 1.75 and 1.35; cyclin A, 9.27% and 3.95%; Ki-67, 34.9% and 23.3%, respectively). CONCLUSION: Our results indicate enhancement of bone marrow angiogenesis in B-CLL and a relationship between microvessel density and the bone marrow infiltration pattern. The study points also to a possible relationship between the bone marrow infiltration pattern and proliferative activity of bone marrow cells.     

Effects of melatonin on luteinizing hormone secretion in anestrous ewes following dopamine and opiate receptor blockade

In the present investigation we have examined the ability of melatonin to modify the pulsatile LH secretion induced by treatment with a DA antagonist (sulpiride, SULP) or opioid antagonist (naloxone, NAL) in intact mid-anestrous ewes. The experimental design comprised the following treatments-in experiment 1: (1) intracerebroventricular (i.c.v.) infusion of vehicle (control I); (2) pretreatment with SULP (0.6 mg/kg subcutaneously) and then i.c.v. infusion of vehicle (SULP + veh); (3) pretreatment with SULP and then i.c.v. infusion of melatonin (SULP + MLT, 100 microg per 100 microl/h, total 400 microg). In experiment 2: (4) i.c.v. infusion of vehicle (control II); (5) i.c.v. infusion of NAL (NAL-alone, 100 microg per 100 microl/h, total 300 microg); (6) i.c.v. infusion of NAL in combination with MLT (NAL + MLT, 100 microg + 100 microg per 100 microl/h). All infusions were performed during the afternoon hours. Pretreatment with SULP induced a significant (P < 0.01) increase in LH pulse frequency, but not in mean LH concentration, compared with control I. In SULP + MLT-treated animals, the LH concentration was significantly (P < 0.01) higher during MLT infusion, but due to highly increased LH secretion in only one ewe. The significant changes in the SULP + MLT group occurred in LH pulse frequency. A few LH pulses were noted after melatonin administration compared with the number during the infusion (P < 0.05) and after vehicle infusion in the SULP + MLT group (P < 0.05). The i.c.v. infusion of NAL evoked a significant increase in the mean LH concentration (P < 0.001) and amplitude of LH pulses (P < 0.01) compared with these before the infusion. The enhanced secretion of LH was also maintained after i.c.v. infusion of NAL (P < 0.01) with a concomitant decrease in LH pulse frequency (P < 0.05). In NAL + MLT-treated ewes, mean plasma LH concentrations increased significantly during and after the infusion compared with that noted before ( P < 0.001). No difference in the amplitude of LH pulses was found in the NAL + MLT group, but this parameter was significantly higher in ewes during infusion of both drugs than during infusion of the vehicle (P < 0.01). The LH pulse frequency differed significantly (p < 0.05), increasing slightly during NAL + MLT administration and decreasing after the infusion. In conclusion, these results demonstrate that: (1) in mid-anestrous ewes EOPs, besides DA, are involved in the inhibition of the GnRH/LH axis; (2) brief administration of melatonin in long-photoperiod-inhibited ewes suppresses LH pulse frequency after the elimination of the inhibitory DA input, but seems to not affect LH release following opiate receptor blockade.     

A fragment of chloroplast DNA was transferred horizontally,probably from non-eudicots,to mitochondrial genome of <Emphasis Type="Italic">Phaseolus</Emphasis>

The mitochondrial genomes of some Phaseolus species contain a fragment of chloroplast trnA gene intron, named pvs-trnA for its location within the Phaseolus vulgaris sterility sequence (pvs). The purpose of this study was to determine the type of transfer (intracellular or horizontal) that gave rise to pvs-trnA. Using a PCR approach we could not find the respective portion of the trnA gene as a part of pvs outside the Phaseolus genus. However, a BLAST search revealed longer fragments of trnA present in the mitochondrial genomes of some Citrus species, Helianthus annuus and Zea mays. Basing on the identity or near-identity between these mitochondrial sequences and their chloroplast counterparts we concluded that they had relocated from chloroplasts to mitochondria via recent, independent, intracellular DNA transfers. In contrast, pvs-trnA displayed a relatively higher sequence divergence when compared with its chloroplast counterpart from Phaseolus vulgaris. Alignment of pvs-trnA with corresponding trnAfragments from 35 plant species as well as phylogenetic analysis revealed that pvs-trnA grouped with non-eudicot sequences and was well separated from all Fabalessequences. In conclusion, we propose that pvs-trnA arose via horizontal transfer of a trnA intron fragment from chloroplast of a non-eudicot plant to Phaseolus mitochondria. This is the first example of horizontal transfer of a chloroplast sequence to the mitochondrial genome in higher plants.